US 7003873 B2
A method of making a gaseous fluid data sensor assembly for acquiring data regarding the ambient environment adjacent a surface of an airframe with adjacent air speeds below 40 knots (or another aerodynamic structure with low speed gaseous fluid flow adjacent thereto) having a flexible substrate adhesively conforming to the airframe surface, a conformable cover layer and a relatively thin air data sensor for sensing air pressure between the substrate and the cover layer. The method includes forming a flexible printed circuit on a polymeric film, attaching thin air data sensor to the printed circuit and attaching a flexible substrate to form a conformal air data sensor. The method may also include attaching a data acquisition circuit to the printed circuit and may still further include providing an optical interconnection between the air data sensor and the data acquisition circuit.
1. A method of fabricating an air data sensor assembly comprising the steps of:
a. forming a flexible printed circuit on a polymeric film having at least one aperture in the film and flexible printed circuit;
b. attaching a relatively thin air data sensor to the flexible circuit adjacent to and in fluid communication with the aperture; and
c. attaching a flexible substrate having an adhesive layer to the air data sensor and flexible printed circuit resulting in a conformable air data sensor assembly for sensing an air parameter in the air adjacent the polymeric film using the air data sensor via the aperture.
2. The method of
b1. attaching a data acquisition circuit to the flexible printed circuit.
3. The method of
4. The method of
d. storing the plurality of assemblies in roll form.
5. The method of
d. storing the plurality of assemblies in roll form with a release layer attached to the adhesive layer.
6. The method of
d. initially attaching a release layer to the adhesive layer.
7. The method of
e. subsequently removing the release layer; and
f. installing the conformable air data sensor assembly on a surface for which air data in a boundary layer adjacent the surface is to be sensed.
8. The method of
9. The method of
10. The method of
11. The method of
12. The method of
13. The method of
14. The method of
d. filling the spaces with epoxy or flexible potting compound.
15. The method of
e. attaching an optical fiber interconnect layer to at least one of the components.
16. The method of
17. The method of
18. The method of
19. The method of
20. The method of
21. The method of
d. applying pressure between the conformable air data sensor assembly and a surface adjacent which air data is to be taken such that the air data sensor assembly closely conforms to the surface to which it is attached.
22. The method of
d. removing the release layer from the adhesive layer.
This application is a division of U.S. patent application Ser. No. 09/757,443, titled Conformal Fluid Data Sensor, filed Jan. 9, 2001 now U.S. Pat. No. 6,662,647. This application claims the benefit of and expressly incorporates by reference the entirety of U.S. patent application Ser. No. 09/757,443.
The present invention relates to the field of fluid data sensing, including airborne vehicle instrumentation, more particularly, to sensors for measuring one or more ambient air parameters adjacent an airflow structure such as an airfoil of an aeronautical structure or an airflow structure in a gaseous fluid flow apparatus such as (but not limited to) a forced air convection heating system.
The aviation community has needed ambient air parameter measurements since the advent of instrumented flight. However, prior art sensor technology was typically not able to provide sufficient resolution in a utilitarian form and at an affordable cost for measurement of dynamic pressures associated with air speeds below 40 knots. For this reason, helicopters and V/STOL (vertical/short takeoff and landing) aircraft used active sensing technologies such as radar and laser optical systems with consequent increases in complexity and cost and attendant issues of reliability. In addition, prior art air data sensors characteristically had salient (projecting) profiles with respect to the structural members to which they were attached. The present invention overcomes such shortcomings of the prior art by providing an apparatus capable of measuring temperature and pressure with high resolution regardless of dynamic pressure, in harsh environments and at extreme temperatures while having a streamlined profile integrated with or conforming to the aerodynamic structure on which it is mounted. As used herein, airborne vehicle and aeronautical structure each mean any apparatus intended for passage through air, around which air may be conducted, or through which air is intended to pass, such as aircraft (whether fixed wing or rotary wing), spacecraft, self-powered and un-powered- projectiles (such as missiles and artillery projectiles), and gaseous fluid propulsion machinery (such as turbo-machinery, jet engines, rocket engines, and the like).
Referring now to the Figures, and most particularly to
Referring now most particularly to
As shown in
The optical fibers in layer 28 may be collected and terminated in standard optical fiber cable connectors. The optical fiber cable connectors are connected to a universal signal conditioner and remote input/output unit in block 30. Block 30 converts the optical signals to air temperature and pressure signals, which are used by the Air Data Computation Block 32 to compute altitude and airspeed from the pressure and temperature according to well-known techniques.
The present invention may be used to provide a minimally invasive pressure measuring instrument for characterizing the boundary layer fluid flow on an aerodynamic surface such as an airplane wing or a inside turbo-machinery such as a turbine engine. By conforming closely to the contour of the surface to which it is attached, there will be minimal or even negligible effect on the fluid flow characteristics in the boundary layer being sensed.
In the practice of the present invention, the air data sensor (such as an air pressure sensor 20), a data communications network (in layer 28), data acquisition circuits 22 and mechanical support are all combined in a single ultra low profile conforming package 12. The package or patch 12 includes a conformal layer 34 for environmental protection which includes a plurality of ports or apertures 36. Layer 34 is preferably a fluoropolymer film such as that manufactured by the 3M Company of St. Paul, Minnesota under the product number 500 as aircraft paint replacement film in thicknesses of 3.5 to 10 mils. In addition to providing a protective cover, film 34 serves as a flexible layer for mounting the components of the system in a manner to be described infra.
Referring now again to
The optical fiber layer 28 is a flexible substrate preferably formed of polyimide about 200 microns thick to provide optical interconnections between the sensors 20 and the data acquisition circuit 22 and to an optical fiber to waveguide coupler 46, which has a strain relief 48 for a multimode fiber optic cable 50 connecting the instrument package 12 to high temperature data processor 32 (see
Referring now to
The instrument package 12 is fabricated by creating the flexible printed circuit 41 on cover layer or film 42, after which components 20, 22, and 24 are electrically connected via solder connections 42. Epoxy layer or flexible potting compound 44 is applied to fill the spaces adjacent components 20, 22, and 24, and the optical fiber interconnect layer 28 with coupler 46 is attached to the components and epoxy layer. The coupler 46 and the pressure sensitive adhesive layer 40 may be attached to the flexible substrate layer 28 before or after assembly to the remainder of package 12.
Referring now to
Referring now to
In practice, the instrument package 12 of the present invention may be fabricated and stored in roll form with the release layer attached, until it is desired to install the package 12 on an airframe member, at which time the package and release layer is unrolled, the release layer removed, and the package or patch 12 applied by hand pressure to the surface adjacent which air data is to be taken. The cable 50 is preferably connected via conventional fiber optic cable connectors to data processing equipment (not shown) to provide air data for the boundary layer adjacent the surface to which patch 12 is attached. The overall thickness of instrument package 12 is about 10 mils or 0.010 inches thick.
This invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention. For example, the present invention may be used to advantage on an interior surface of a turbine engine or other structure requiring streamlined airflow. Furthermore, the present invention may be used in conventional gaseous fluid flow structures such as process equipment and space heating.